It was originally set up to cater for folk photographing low flyhing in the Welsh mountains, particularly around the Mach Loop. So it's historically a subscription service with its own ICAO lookup database for military aircraft in the UK, which is very accurate indeed...

Now anyone can subscribe to 360radar, but it is limited to the UK and a small part of northern Europe. It's not the cheapest service, but if you're an aviation photographer in the UK it and its linked community are a key resource.